1. Field of the Invention
The disclosure relates to knives. In particular, the disclosure relates to spring assisted folding knives.
2. Description of Related Art
Conventional spring assisted knives utilize a Cam-Over-Center design as shown in FIGS. 1 and 2. FIG. 1 shows a pin attached to a blade of a folding knife. The pin is secured to the blade in an off-center position. A bar under tension is applied to the pin as a blade driver. When the blade is unlocked from the liner and returned to the knife body, the user rotates the blade counterclockwise (CCW) direction, thereby closing the knife. Once the pin on the blade rotates past center, the cam action of the bar against the pin keeps the blade in the closed position.
When the user is ready to open a spring assisted knife, the user may use a thumb stud or some other feature on the blade to initiate blade movement. FIG. 2 illustrates how the blade is driven once the blade/pin are beyond center. When the knife is in the orientation shown in FIG. 2, the blade is rotated in a direction that is reverse from the CCW direction used to close the knife. Thus, a user rotates the blade in a clockwise (CW) direction to open the knife and the action is assisted by the bar under tension. Unimpeded, the blade should rotate to a fully locked position. However, the bar is limited by the amount of action it can apply to the blade because it does not follow the pin throughout its entire travel. Consequently the force applied to the blades in the prior designs are limited to 90° of blade rotation, at best.